A phosphor plate for light emitting diodes (LEDs) is manufactured using glass frit and a phosphor. The phosphor plate has a complex structure in which an inorganic crystal-based phosphor is distributed in a glass matrix. When a phosphor plate is manufactured by sintering glass frit, structural defects such as pore formation occur. Such structural defects result in lower strength of the phosphor plate. The structural defects cause destruction or damage to LEDs since LEDs are subjected to physical damage during subsequent processes such as abrasive polishing, dicing, and packaging processes and also when LEDs are driven for a long period of time.
For example, the phosphor included in the phosphor plate may be damaged or separated when the phosphor plate is subjected to abrasive polishing. When the phosphor is damaged, the luminous flux of the phosphor plate may decline, the luminous efficiency may be lowered, or color qualities such as color homogeneity in the phosphor plate may be degraded. When the phosphor is separated from the phosphor plate, a content of the phosphor in the phosphor plate may be reduced, resulting in decreased luminous flux and degraded color quality.